My baby betta needs a heater for the Winter. She has a half gallon tank and I was wondering maybe I can get her a half gallon heater. I searched everywhere online and in the stores but I couldn't find one. Can I have some help?

Zoo med makes small heaters specifically meant for bowls that you can get at any pet store, but even with her being a baby I would suggest moving her into a 2.5 gallon if you can it is healthier for them to have lots of room to grow and play a half gallon is very small.